下列结论中不正确的是( )．
A．若f'(x0)=0，f"(x0)=0，则不能确定点x=x0。是否为函数的极值点
B．若x=x0是函数f(的极值点，则f'(x0)=0或f'(x0)不存在
C．函数f(在区间(a，内的极大值一定大于极小值
D．f'(x0)=0及f'(x0)不存在的点x=x0，都可能是f(的极值点
参考答案：C
解析：[分析] 本题主要考查函数的极值存在的条件及极大(小)值的概念．这里涉及的基本概念主要有： (1)驻点不一定是极值点． (2)极值点可以在驻点处取到或在导数不存在的点处取到． (3)极值是局部性质，因此极大值不一定大于极小值．例如，正常情况下小学学生年龄最 (极)大的不会大于中学生中年龄最(极)小的所以选C
| 完形填空。 | ||||
| Nowadays we call see more and more electric bikes in the street. Electric bikes are easy to 1 and they can run faster than ordinary bikes. So they become very 2 in many cities in China now. But the electric bikes also 3 many traffic accidents happen. So the Chinese government plans to make a new 4 for the electric bike riders (骑车者). If 5 electric bike is heavier than 40 kilos and it can go 6 than 20 kilometers an hour, its rider must get a license (执照). It means riders have to pass driving test 7 they ride their electric bikes on the road. People have different ideas about the rule. Some people like the rule 8 they think it will make the street much safer. But some people are not 9 the new rule at all. One rider said, "I don't want to get a license or 10 , I don't like too many rules in life." What's your idea, my friends? | ||||
|